Prosthetic shoulder joint

ABSTRACT

A prosthetic scapular device is provided having a generally cupshaped member, normally of a hemispherical form at least internally, and intracancellous fixation means extending from approximately one half only of the outer surface of the cup. The fixation means, normally in the form of mutually divergent spikes, include long members extending from points adjacent the central radial plane of the relevant cup half and diverge in the same sense from such plane, together with short members on opposite sides of such plane. Preferably, the long members increase in length and divergence from said plane as they approach the cup rim.

United States Patent Scales et al.

( 51 Oct. 3, 1972 154] PROSTHETIC SHOULDER JOINT [73] Assignee: NationalResearch Development Corporation, London, England [22] Filed: July 29,1970 [21] Appl. No.: 59,083

[30] Foreign Application Priority Data Aug. 25, 1969 Great Britain..42,197/69 [52] US. Cl. ..3/l, 128/92 C [51] Int. Cl. ..'.A61f 1/24[58] Field of Search ..3/1; 128/92 R, 92 C, 92 CA [56] References CitedUNITED STATES PATENTS 3,140,712 7/1964 Hunter 128/92 C FOREIGN PATENTSOR APPLICATIONS 1,552,585 11/1968 France 128/92 C 1,448,955 7/1966France 128/92 CA 976,768 4/1964 Germany 1 28/92 CA 7/1953 France..128/92 C OTHER PUBLICATIONS Neer Shoulder Prostheses, VitalliumSurgical Appliance (Catalog), Austenal Medical Div., Howmet Corp., NewYork, N.Y., 1964, page 55 relied upon.

Primary Examiner-Richard A. Gaudet Assistant Examiner-Ronald L. FrinksAttorney-Cushman, Darby and Cushman [57] ABSTRACT A prosthetic scapulardevice is provided having a generally cup-shaped member, normally of ahemispherical form at least internally, and intracancellous fixationmeans extending from approximately one half only of the outer surface ofthe cup. The fixation means, normally in the form of mutually divergentspikes, include long members extending from points adjacent the centralradial plane of the relevant cup half and diverge in the same sense fromsuch plane, together with short members on opposite sides of such plane.Preferably, the long members increase in length and divergence from saidplane as they approach the cup rim.

7 Claims, 17 Drawing Figures PROSTI-IETIC SHOULDER JOINT This inventionconcerns prosthetic shoulder joint devices and it is intended to permitcomplete replacement of shoulder joints affected by disease or injury.

It appears, at least from the currently available range of prostheticdevices, that no successful attempt has been made previously to permitcomplete shoulder joint replacement. The available devices includehumeral head prostheses, but no associated glenoid prosthesis. Moreover,implantation of the existing humeral head devices usually involvesremoval of the rotator cuff muscles, and the resultant implant is liableto dislocate.

r The present invention seeks to alleviate this situation by effectivelyproviding a prosthetic glenoid cavity for co-operation with a prosthetichumeral head.

According to the invention there is provided a prosthetic scapularglenoid device comprising a generally cup-shaped member havingintracancellous fixation means rigidly connected to or integral with,and extending from, approximately one half only of the outer surface ofsaid member.

The glenoid cup, as said member may be termed, will normally besubstantially hemispherical, at least over its inner surface.

In a preferred form the fixation means comprise a plurality of mutallydivergent spike-like elements, including both long and short spikes. Thelonger spikes stem from a succession of points adjacent the centralradial plane of the relevant half of the cup, and they diverge in thesame sense slightly away from such plane. As will be seen hereinafterfrom an illustrated embodiment the longer spike of greatest length anddivergence from the central radial plane is that closest to the rim ofthe cup.

The associated shorter spikes are located on both sides of thesuccession of larger spikes and within the relevant half cup surface.

As an indication of the more particulanshaping and dimensioning of adevice as just described, the cup has an internal diameter of about Ainch and external diameter of about 1 inch, the longer spikes range fromabout a .to 1 inch in length with respective divergence of about 9 and13 from the central radial plane, and the shorter spikes are about A;inch in length.

While it is presently preferred to employ spike-like elements asfixation means, this is not essential. For example, the role of some orall of the longer spikes may be served by an appropriately shaped weband the role of some or all of the shorter spikes may be served by ribs.

An associated prosthetic humeral head device for use with a cup as justdescribed may be of any suitable form given that it comprises aball-like head part which can, when the device is implanted, bepresented to the cup to form an appropriate ball-and-socket joint. Thispoint will become clearer after consideration of the illustratedembodiment hereinafter and the desired relative attitudes of the jointparts.

However, a preferred form of the latter device comprises a rod-likeintramedullary fixation part integrally formed with a ball-like humeralhead part at one end, the longitudinal axis of the head part beingturned from that of the fixation part by about 45.

For a fuller understanding of the present invention, the same will nowbe described by way of example with reference to the accompanyingdrawings, in which:

FIG. 1 shows one embodiment of a glenoid device according to theinvention in plan view,

FIGS. 2 and 3 are side views of the embodiment of FIG. 1 as seen in thedirections indicated at A and B,

FIGS. 4, 5 and 6 are sectional views respectively takenatC-C,D-D,andEEin FIG. 1,

FIGS. 7 and 8 are sectional views respectively taken at F F, and G G inFIG. 2,

FIG. 9 is a sectional view taken at H H in- FIG. 3,

FIG. 10 is a plan view of the cup of FIG. 1 showing the co-ordinatepositions of the fixation means,

FIG. 11 is a diametral section of the cup of FIG. 1,

FIGS. 12 and 13 respectively show an associated embodiment of a humeralhead device according to the invention in plan and side views,

FIGS. 14 and 15 are sectional views respectively taken at l I, and J Jin FIG. 13, and

FIGS. 16 and 17 diagrammatically illustrate the manner of implantationof the illustrated devices.

The illustrated glenoid device comprises a substantially hemisphericalcup 1 and a plurality of mutually divergent, spike-like fixation means 2to 6 of the preferred form described above. It will be seen that thespikes 2 to 6 extend from substantially one half of the exterior of thecup as separated by the diametral plane in the direction A of FIG. 1,the longer spikes 2, 3 and 4 extend from a succession of points adjacentthe central radial plane in the direction B of FIG. I and diverge fromthe latter plane in the same sense, and the shorter spikes 5 and 6 arelocated on opposite sides of the succession of longer spikes. The twospikes 2 and 3 of the longer spikes are of similar length and similarlateral inclination to the central radial plane, while spike 4 nearestthe rim of the cup is of greater length and lateral inclination thanspikes 2 and 3.

More particular details of the illustrated glenoid device are given bythe following table of dimensions, each dimension being denoted by areference numeral and letter of which the former denotes the relevantfigure of the drawing and the latter the dimension in that figure, andthe dimension value being given in inches unless otherwise denoted as anangle.

la 13 6a 22.5 8b 9/l6 I0:- 0.060 10h 30 l3 I3 25 1011 0.ll0 Ila 0.750

40 13 7b l3 9!; 0.125 10e 0.150 Ilb 0.960

5a 25 76 9/]6 10a 0.245 10] 0.030 llc 0.067

5b 7 8a 9 10!) 0.215 10g 0.235 lld 0.547

The associated humeral device illustrated by FIGS. 12 to 15 is detailedin similar manner by the following table:

Regarding materials: the illustrated devices can be conveniently made ofcobalt-chromium alloy as is often the case with such devices. Howeverthis is not essential since the glenoid device may equally well be madeof titanium housing a high-density polythene insert as a bearing liner.The liner is conveniently of hemispherical cup form, retained by aspring circlip seated in an annular groove in the main cup adjacent toits rim. More generally, the associated devices may be made of anysuitable materials, be they metal, plastics, ceramic, composite orcombination thereof.

Lastly, it is appropriate to indicate the manner of implantation, andthis is effected by reference to FIGS. 16 and 17.

The glenoid is excavated and cancellous bone removed to permit cementingor grouting of the device in position, as shown, with acrylic resin orother suitable material. When correctly positioned the cup should lie atan angle of about 60 to the horizontal plane as viewed anteriorly, andshould lie at an angle to 13 to the plane of the glenoid cavity asviewed from above.

The humeral device is similarly cemented or grouted into a preformedhole made in the humeral marrow cavity so that the balllike head partengages the glenoidal device cup as shown.

We claim:

1. A prosthetic device for use as a human shoulder joint replacement,which device is designed to be used together with a selfhardening orself-curing gap-filling agent within cavities cut in the bone of thescapular glenoid and humerus, comprising:

a scapular glenoid first bearing member having a part-spherically shapedfirst bearing surface; intracancellous first fixation means connected orintegrally formed with said first member;

said first fixation means projecting from said first member along asuccession of points adjacent a symmetrically disposed radial plane ofsaid first surface, said succession of points extending between acentral portion and one edge portion of said first member as intersectedby said plane, said first fixation means projecting further from saidmember at said one edge portion than from said central portion, and saidfirst fixation means diverging from said plane to one side thereof withincreasing projection from said first member; humeral second bearingmember having a partspherically shaped second bearing surfacecomplementary to and rotatably received by said first bearing surface;

and intra-medullary second fixation means connected or integrally formedwith said second member;

said second fixation means including an elongate tapered projecting fromsaid second member to terminate in a tapered stem.

2. A device according to claim 1 wherein said fixation means projectfrom said first bearing member by progression along said succession ofpoints towards said edge portion, and said second fixation meansprojects from said second bearing member while turning through an angleof about 45 relative to the longitudinal axis of said tapered stem.

3. A prosthetic device for use as a scapular glenoid replacement, whichdevice is designed to be used together with a self-hardenin orself-curing gap-filling agent within cavities cut in e bone of thescapular, which device comprises:

a cup to act as a scapular glenoid replacement and having apart-spherically shaped inner surface, a generally convex outer surface,and a rim joining said inner and outer surfaces;

intracancellous fixation means connected or integrally formed with saidcup and for bonding in said gap-filling agent;

said fixation means projecting from said outer surface along asuccession of points adjacent a plane which is radially andsymmetrically disposed relative to said inner surface; I

said succession of points extending between a central portion of saidouter surface and an edge portion of said outer surface where said planemakes one intersection with said rim;

said fixation means projecting further from said outer surface at saidedge portion than from said central portion;

and said fixation means diverging from said plane to one side thereofwith increasing projection from said outer surface.

4. A device according to claim 3 wherein the divergence of said fixationmeans from said plane increases with progression along said successionof points toward said edge portion, said divergence being in the rangeof about 9 to l 3 relative to said plane.

5. A device according to claim 3 wherein said fixation means comprise aplurality of spike-like members, the geometrical projections of which insaid plane are mutually divergent.

6. A device according to claim 3 wherein said fixation means projectfrom said cup by distances in the range of about /2 inch to 1 inch, andfurther comprising relatively shorter fixation means projecting fromsaid cup outer surface adjacent the first-mentioned fixation means andon both sides thereof relative to said succession of points.

7. A device according to claim 4 in combination with prosthetic humeraldevice comprising a head part having a spherically shaped bearingsurface complementary to and received in said cup inner surface, and afixation member projecting from said head part through a neck portionand terminating in a tapered stem, the longitudinal axis of said stembeing disposed at about distances in the range of about 1 inch to 1 inchthe 45 inclination relative to that of said neck portion addivergence ofsaid first fixation means increases in the range of about 9 to 13relative to said plane with joining said head part.

1. A prosthetic device for use as a human shoulder joint replacement,which device is designed to be used together with a self-hardening orself-curing gap-filling agent within cavities cut in the bone of thescapular glenoid and humerus, comprising: a scapular glenoid firstbearing member having a partspherically shaped first bearing surface;intracancellous first fixation means connected or integrally formed withsaid first member; said first fixation means projecting from said firstmember along a succession of points adjacent a symmetrically disposedradial plane of said first surface, said succession of points extendingbetween a central portion and one edge portion of said first member asintersected by said plane, said first fixation means projecting furtherfrom said member at said one edge portion than from said centralportion, and said first fixation means diverging from said plane to oneside thereof with increasing projection from said first member; ahumeral second bearing member having a part-spherically shaped secondbearing surface complementary to and rotatably received by said firstbearing surface; and intra-medullary second fixation means connected orintegrally formed with said second member; said second fixation meansincluding an elongate tapered projecting from said second member toterminate in a tapered stem.
 2. A device according to claim 1 whereinsaid fixation means project from said first bearing member by distancesin the range of about 1/2 inch to 1 inch, the divergence of said firstfixation means increases in the range of about 9* to 13* relative tosaid plane with progression along said succession of points towards saidedge portion, and said second fixation means projects from said secondbearing member while turning through an angle of about 45* relative tothe Longitudinal axis of said tapered stem.
 3. A prosthetic device foruse as a scapular glenoid replacement, which device is designed to beused together with a self-hardening or self-curing gap-filling agentwithin cavities cut in the bone of the scapular, which device comprises:a cup to act as a scapular glenoid replacement and having apart-spherically shaped inner surface, a generally convex outer surface,and a rim joining said inner and outer surfaces; intracancellousfixation means connected or integrally formed with said cup and forbonding in said gap-filling agent; said fixation means projecting fromsaid outer surface along a succession of points adjacent a plane whichis radially and symmetrically disposed relative to said inner surface;said succession of points extending between a central portion of saidouter surface and an edge portion of said outer surface where said planemakes one intersection with said rim; said fixation means projectingfurther from said outer surface at said edge portion than from saidcentral portion; and said fixation means diverging from said plane toone side thereof with increasing projection from said outer surface. 4.A device according to claim 3 wherein the divergence of said fixationmeans from said plane increases with progression along said successionof points toward said edge portion, said divergence being in the rangeof about 9* to 13* relative to said plane.
 5. A device according toclaim 3 wherein said fixation means comprise a plurality of spike-likemembers, the geometrical projections of which in said plane are mutuallydivergent.
 6. A device according to claim 3 wherein said fixation meansproject from said cup by distances in the range of about 1/2 inch to 1inch, and further comprising relatively shorter fixation meansprojecting from said cup outer surface adjacent the first-mentionedfixation means and on both sides thereof relative to said succession ofpoints.
 7. A device according to claim 4 in combination with prosthetichumeral device comprising a head part having a spherically shapedbearing surface complementary to and received in said cup inner surface,and a fixation member projecting from said head part through a neckportion and terminating in a tapered stem, the longitudinal axis of saidstem being disposed at about 45* inclination relative to that of saidneck portion adjoining said head part.